Motor road roller

ABSTRACT

The invention relates to a motor-driven pavement roller having rigid supporting frame ( 1 ) that is braced on a pair of operating tools, and at least one of these operating tools is pivotable and is connected to a  -shaped frame ( 7 ), and the  -shaped frame ( 7 ) is connected to rotary axes, which are perpendicular to one another, of the operating tool and of a pivot shaft ( 9 ), and the pivot shaft ( 9 ) serves to pivot the operating tool relative to the supporting frame ( 1 ). To enable increasing the working output of the pavement roller and widening the roller pivot angle, the invention provides that the axes of the operating tool are mounted in intersecting fashion on the  -shaped frame ( 7 ).

The invention relates to a motor-driven pavement roller as defined bythe preamble to claim 1.

The invention can be used in road construction, and in particular fortechnical means for compacting road construction compositions, that is,for pavement rollers.

Motor-driven pavement rollers, both with a center pivot drivensupporting frame and with a rigid supporting frame, are used in roadconstruction. The refinement according to the invention relates topavement rollers having a rigid supporting frame and to the roller pivotsystem.

From Russian Patent Disclosure RU 2024673, a construction of amotor-driven pavement roller having a rigid supporting frame is known.The supporting frame is braced from below on a pair of operating toolsembodied as rollers. Each roller unit includes one roller. To steer themotor-driven pavement roller, at least one of the roller units must beembodied pivotably about a steering axle that is vertical to thesupporting frame. Each of the roller units has a

-shaped (U-shaped) frame, between the legs of which the roller isrotatably supported about its center axis. This frame embraces theroller and is braced on the center axis of the roller. The steeringmechanism includes a vertical pivot shaft, which matches the steeringaxle. The vertical pivot shaft is mounted on the

-shaped frame and more precisely on the supporting frame thereof. Thepivot shaft is a part of the rocker bearing of the supporting frame. Thepivot shaft is kinematically connected to a drive mechanism. Usually, ahydraulic cylinder is used as the drive mechanism. The steeringmechanism is embodied such that geometric center axes and steering axlesextend perpendicular to one another and intersect one another. It isunderstood that the physical center axes and pivot axes extend onlyvertically to one another and do not intersect.

The primary disadvantage of this known construction is that the steeringmechanism employed has a limited pivot angle. This offers no opportunityof increasing the width of the rolled strip and thus of increasing thework output of the compacting operations. This disadvantage pertains toa pavement roller having two steerable roller units. Moreover, this kindof steering mechanism substantially reduces the freedom of motion of thepavement rollers that are equipped with only one steerable roller unit.Furthermore, the pivoting device of the

-shaped frame, which includes a bearing unit, a drive mechanism, and thekinematic connection of the drive mechanism to the pivot shaft, isdisposed on the supporting frame and thus these elements are connectedto one another mechanically. This makes the entire construction of thesteering mechanism more difficult and makes it harder to repair.

From German Patent DE 198 13 475 C1, a motor-driven pavement roller witha rigid supporting frame and with at least one operating tool embodiedas a roller is known. At least one roller unit is disposed on thesupporting frame. The roller unit comprises a

-shaped (U-shaped) frame and a horizontal, cylindrical roller. Theroller is supported rotatably between the free ends of the legs of the

-shaped (U-shaped) frame, about the center axis thereof. On its sidesremote from the free ends, the legs are connected to one another by acrossbar, extending parallel to the center axis, of the

-shaped (U-shaped) frame. The roller unit is disposed pivotably on thesupporting frame about a steering axle. The frame is disposed uprightbelow the supporting frame, and the free ends of the legs of the frame,which extend approximately parallel to the steering axle, pointdownward, and the steering axle stands vertically on both the crossbarand the center axis. If the motor-driven pavement roller has two rollerunits, then both of them are steerable, and one of the roller units canbe supported in pendulum fashion, in order to compensate for differencesin the slope of the underlying surface. Steering a steerable roller unitutilizes a steering mechanism having a hydraulic cylinder that isdisposed obliquely in the travel direction between the supporting frameand the frame.

From German Patent Disclosure DE 37 12 099 A1, a motor-driven pavementroller with a rigid supporting frame and with two operating tools, eachembodied as a roller, is known. Both rollers are supported rotatablyabout their center axis in a

-shaped (U-shaped) frame. Each of the two frames rests with itscrossbar, which connects the two legs, on the supporting frame. Bothframes are supported pivotably each about its own steering axle thatstands upright both on the crossbar of the respective frame and on thecenter axis of the respective roller supported rotatably between thelegs of that frame.

From German Utility Model DE 2002 00 88 U1, a motor-driven pavementroller with a rigid supporting frame and with two operating tools, eachembodied as a roller, is known. Each of the rollers is rotatablysupported about its center axis in a frame. The frames are eachconnected in articulated fashion via a center pivot with a verticalsteering axle to the centrally disposed supporting frame, on its opposedface ends. One of the two rollers can be steered relative to thesupporting frame and the remaining roller, or else both rollers can besteered in the same or opposite directions with identical or differentsteering angles. Thus the motor-driven pavement roller can even driveobliquely to the orientation of its supporting frame, in the so-calledpress-on tire offset, as a result of which an increase in the width ofthe compacted strip can be obtained.

A common feature of the known motor-driven pavement rollers is that inthe working mode they allow an only limited width of the compactedstrip. Moreover, they have a greatly restricted maneuverability, sincethe steering mechanisms used and/or the articulated connections of thesteerable rollers to the supporting frame permit only a restrictedoblique position of the rollers relative to the supporting frame. Anadditional disadvantage of the known motor-driven pavement rollers istheir poor driving behavior, associated with a restricted freedom ofmotion along the routes between locations where they are used.

It is the object of the invention to increase the working output incompacting operations by means of increasing the width of the compactedstrip, specifically by widening the roller pivot angle. A further objectis to improve the freedom of motion of the pavement roller and toimprove the repair conditions of the roller pivot system.

This object is attained by the features of claim 1.

The stated object is attained as follows.

The motor-driven pavement roller has a rigid supporting frame, which isbraced at the bottom on a pair of operating tools, each preferablyincluding at least one roller. At least one of these operating tools isembodied as a pivoting device that is pivotable about a steering axlethat stands vertically on the supporting frame. The pivoting deviceincludes a U- or

-shaped frame between the legs of which at least one roller of anoperating tool is enclosed, supported rotatably about a horizontalrotary axis. The crossbar, extending parallel to the horizontal axis, ofthe U- or

-shaped frame is coupled to the supporting frame by means of a jointhaving a vertical pivot shaft. The pivot shaft matches the steering axleof the respective pivoting device. The

-shaped frame is disposed horizontally, so that the crossbar is locatedon the outside. The crossbar is coupled to a front part of thesupporting frame.

This front part can be built in in such a way that relative to themiddle part of the supporting frame, it can be displaced back and forthin the travel direction of the pavement roller.

The effect of the proposed refinement can be enhanced markedly if atleast one operating tool includes a pair of dissimilar rollers.

A first roller of a pair of dissimilar rollers can be embodied as aroller, supported rotatably about its center axis, in the form of ahorizontal circular cylinder, which is for instance hollow andoptionally can filled with a liquid, for instance, or a pourablesubstance, such as sand, and which can be manufactured for instance ofmetal. A second roller of a pair of dissimilar rollers can be embodiedas a plurality of wheels, rotatably supported on a common wheel axle,for instance wheels of solid rubber.

Such dissimilar rollers can be combined into a carriage similar to abogie with the aid of a pair of lateral beams.

A middle part of such lateral beams can be coupled, by means of a jointprovided with a horizontal axis, to the

-shaped frame that for instance embraces the lateral beams. If the frameembraces the lateral beams, then the lateral beams are disposed betweenthe legs of the frame. The

-shaped frame, in turn, is coupled to the front part of the supportingframe. The carriage is mounted pivotably about the horizontal axis ofthe joint. This can serve to compensate for unevenness of the ground,and both rollers of a pair of dissimilar rollers mounted on the carriagestays in contact with the ground. Alternatively or in addition, thecarriage can be mounted in pivotably drivable fashion about thehorizontal axis of the joint. As a result, by actively pivoting it aboutthe horizontal axis of each carriage, selectively one of the twodissimilar rollers, or both, come into contact with the ground. This canbe advantageous for instance if the motor-driven pavement roller drivesitself from one location to another where it is to be used. Forinstance, if one of each of the dissimilar rollers of two carriagesprovided on one motor-driven pavement roller is embodied as a pluralityof solid rubber wheels or the like mounted on a common wheel axle, thenas a result the driving performance and along with it the freedom ofmotion of the motor-driven roller along routes between the locations ofuse can be improved considerably in comparison to the prior art.

Furthermore, both operating tools can each be pivotable about their ownsteering axles that extend parallel to one another.

Preferably, a steering mechanism of a pivoting device includes twohydraulic cylinders. The two hydraulic cylinders are disposed inopposite directions obliquely to a longitudinal axis of the supportingframe of the motor-driven pavement roller. Per hydraulic cylinder, afirst end of each is connected pivotably to the supporting frame aboutan articulated axle extending parallel to the steering axle. Each secondend of the two hydraulic cylinders is connected pivotably to the frame,for instance to the crossbar thereof, about an articulated axleextending parallel to the steering axle. The two hydraulic cylinders arepivotably connected to the frame by their second ends, on the sides ofthe frame opposite the steering axle. In the event of a steering angleof 90° or more, this ensures that at least one of the two hydrauliccylinders effects a return motion of the pivoting device into its outsetposition, in which the crossbar extends orthogonally to the longitudinalaxis of the supporting frame of the motor-driven pavement roller. Thusthe steering mechanism permits a steering angle of a steerable pivotingdevice by up to 90° in both directions relative to the longitudinal axisof the supporting frame, and thus in a motor-driven pavement rollerhaving two steerable pivoting devices, it enables travel transversely tothe longitudinal axis of the supporting frame, along with a considerableincrease in the width of the compacted strip. To prevent themotor-driven pavement roller from tipping sideways, the steering anglecan be restricted to an angle of less than 90° in both directions.Alternatively or in addition, at least one pivoting device can beequipped with two identical or different rollers, which prevents themotor-driven pavement roller from tipping over onto its side. In aversion having one or two pivoting devices, a considerably improvedmaneuverability of the motor-driven pavement roller is obtained as well.

The invention will be described in further detail in conjunction withthe drawings. In the drawings:

FIG. 1 shows the general view of the motor-driven pavement roller withone pivoting device;

FIG. 2 shows the general view of the steering mechanism of a pivotingdevice, with the intersecting rotary axes and pivot axes;

FIG. 3 shows the general view of the motor-driven pavement roller withtwo pivoting devices;

FIG. 4 schematically shows a plan view of the pavement roller with twopivoting devices;

FIG. 5 shows the general view of the motor-driven pavement roller withoperating tools which are embodied by a pair of dissimilar rollers;

FIG. 6 schematically shows the pavement roller of FIG. 5 in plan view;and

FIG. 7 shows the diagram for explaining the mode of operation inperforming compacting operations with the motor-driven pavement rollerof FIG. 5.

The motor-driven pavement roller (FIG. 1) includes a rigid supportingframe 1. An engine 2 and a cab 3 for the driver are mounted on thesupporting frame 1. The frame 1 is braced from below on a pair ofoperating tools in the form of smooth rollers 4 and 5. One of theoperating tools is embodied as a pivoting device, disposed pivotably onthe supporting frame 1 about a steering axle. The pivoting deviceincludes the pivotable roller 4, which is coupled, rotatably supportedabout a horizontal rotary axis 6, to a

-shaped frame 7, which is disposed horizontally. When the frame 7 isdisposed horizontally, its legs and a crossbar connecting the two legsextend in a plane that is parallel to the longitudinal axis 16 of thesupporting frame 1. The frame 7 is connected to the end of thesupporting frame 1 by means of a steering mechanism. The steeringmechanism includes a joint, which comprises a bush 8 and a pivot shaft 9forming a steering axle. More precisely, the supporting frame 1 isrigidly coupled to a vertical pivot shaft 9. The pivot shaft 9 islocated outside the horizontal projection of the operating tool, or itsroller.

One of the possible embodiments of the pivot drive mechanism is shown inFIG. 2. Here, the force-operated pivoting motion of the

-shaped frame 7 in the joint is effected by means of a hydrauliccylinder 10, both of which are connected pivotably to the frame 7 and tothe structural part of the supporting frame 1. The pivot angle of theroller can attain 90°. This is witnessed by the fact that point “A” ofthe rod mounting of the hydraulic cylinder 10 shifts on the

-shaped frame 7 to point “B”. The rotary axis 6 of the roller 4 and itspivot shaft 9 are mounted in intersecting fashion on the pavementroller, and their geometrical axes are perpendicular to one another.

In the construction of the motor-driven pavement roller having twopivotable rollers, the pivoting device of each roller is entirelyidentical to the above-described apparatus (FIG. 3).

FIG. 4 schematically shows the pavement roller with two pivot rollers inplan view. In this position, the outward-pivoted rollers double thewidth of the compacted strip. Their pivot angle at the same time is muchless than 90°.

In FIG. 5, a modification of a motor-driven pavement roller with fourrollers is shown. It is described in Soviet Union Patent Disclosure SU1401097. Here, the conventional pivoting device is replaced by arefinement of the invention. Besides the rigid supporting frame 1 withthe engine 2 and the cab 3, the pavement roller has two operating tools.Each of these operating tools has a pair of dissimilar rollers. Oneroller 11 is pneumatic. A second roller 12 is smooth and vibrates. Theserollers 11 and 12 are combined into a carriage with the aid of a pair oflateral beams 13. These lateral beams 13 are connected to the

-shaped frame 7 by means of a horizontal joint 14. The frame is coupledto a front part of the supporting frame 1 with the aid of a joint. Thejoint includes a bush 8 and the vertical pivot shaft 9. Both front partsare embodied movably relative to the middle part of the supporting frame1. The displaceability back and forth of the front parts of thesupporting frame 1 is ensured by providing that they are connected todisplaceable beams 15. The beams 15 are inserted into linear guides ofthe supporting frame 1. These guides have the same orientation as themotion of the pavement roller. An adjusting drive mechanism of the beams15 is not shown in the drawing. Preferably, a hydraulic drive mechanismis employed. The steering mechanism of the operating tools of themulti-roller machine is identical to the construction in FIG. 2. Thespecial feature of this pavement roller is that thanks to thearticulated connection of the lateral beams 13 to the

-shaped frame 7 and to the possibility of changing their angle ofinclination under the influence of a special drive mechanism (not shownin the drawing), it becomes possible for one or the other roller, ortheir combination, depending on the material to be compacted, to comeinto contact with the surface to be compacted.

In FIG. 6, the plan view of a motor-driven pavement roller with fourrollers is shown schematically. In this machine, the width of thecompacted strip can be attained not only by providing that the operatingtools are can be pivoted about a wide angle, but also by providing thattheir undercarriage can also be enlarged, because the front parts of thesupporting frame 1 can be pushed apart by means of the movable beams 15.

The function of the motor-driven pavement roller with the novel pivotingsystem of the operating tools is illustrated taking as an example theuse of the pavement roller with four rollers.

If compacting operations are performed by means of rolling, depending onthe type of material, the user chooses one or the other complete set ofrollers, because the carriages of each operating tool are rotatableabout the horizontal joint 14. The requisite rollers are put intocontact with the surface to be compacted, and the other rollers aresuspended. At the same time, an optimal rolling width is selected bydeflecting the rollers by the requisite angle. This is attained with theaid of the pivoting system according to the invention and in that thefront parts of the supporting frame 1 (FIG. 6) are moved apart. Afterthat, the rolling operation can be performed in accordance with thefunctional diagram in FIG. 7. For instance, the smooth rollers 12 aresuspended when the surface compositions are being compacted, and thepneumatic rollers 11 (position I, FIG. 7) become supporting rollers. Tointensify the soil compaction, taking special aspects of the soil (denseor loose) into account, a complete set of both rollers 11 with pneumatictires and a smooth vibration roller 12 (position Ill, FIG. 7) can beemployed. For compacting an aggregate base, a combination of two rollerscan be employed (position V, FIG. 7). These form a so-called combinationpavement roller. When compacting mixtures of asphalt and concrete, it isappropriate to use a combination of rollers in accordance with positionsII and IV, as well as other combinations, depending on the brand name ofthe asphalt and concrete mixture, the initial temperature of theasphalt, and the ambient temperature.

With a wide range of variation of the roller width and considerableprocess-related technical capabilities of the motor-driven pavementroller with four rollers, a possibility of automating the compactingoperation via an on-board computer is achieved for the first time, usinga software package in the on-board computer.

1. A motor-driven pavement roller having a rigid supporting frame, whichis braced from below on a pair of operating tools, and an operating toolof these is pivotable and is enclosed in a U- or

-shaped frame, and a crossbar of the frame is connected to thesupporting frame by means of a joint having a vertical pivot shaft,characterized in that the frame is disposed horizontally, so that thecrossbar is located on the outside and is coupled to a front part of thesupporting frame.
 2. The motor-driven pavement roller of claim 1,characterized in that the front part of the supporting frame, whichfront part is coupled to the frame, is disposed displaceably back andforth in the travel direction of the motor-driven pavement rollerrelative to the middle part of the supporting frame.
 3. The motor-drivenpavement roller of claim 1, characterized in that an operating toolincludes a pair of dissimilar rollers.
 4. The motor-driven pavementroller of claim 3, characterized in that the pair of dissimilar rollersis combined in a carriage with the aid of a pair of lateral beams. 5.The motor-driven pavement roller of claim 4, characterized in that themiddle part of each lateral beam is coupled to the frame by means of ajoint having a vertical pivot shaft, and the frame is in turn coupled tothe front part of the supporting frame, and the carriage is mountedpivotably about a horizontal axis of the joint.
 6. The motor-drivenpavement roller of claim 5, characterized in that the lateral beams aredisposed between the legs of the frame.
 7. The motor-driven pavementroller of claim 1, characterized in that both operating tools arepivotable.
 8. The motor-driven pavement roller of claim 1, characterizedin that the end of the supporting frame is connected to the pivot shaftand mounted such that it is displaceable back and forth in the traveldirection of the pavement roller relative to the remainder of thesupporting frame.
 9. The motor-driven pavement roller of claim 1,characterized by a steering mechanism for an operating tool that ispivotable about a steering axle, the operating tool including twohydraulic cylinders disposed in opposite directions obliquely to alongitudinal axis of the supporting frame of the motor-driven pavementroller, and per hydraulic cylinder: a first end is connected inarticulated fashion to the supporting frame about an articulated axleextending parallel to the steering axle, and a second end is connectedto the frame in articulated fashion about an articulated axle extendingparallel to the steering axle, on opposite sides of the frame from thesteering axle.